1. Technical Field
The present invention relates to an ink jet recording-targeted non-aqueous ink composition, an ink set, and an ink jet recording method.
2. Related Art
In typical ink jet recording, fine ink droplets are ejected from the nozzle of an ink jet recording head, thereby recording images and characters. Such ink jet recording has been mainly utilized in recording onto a surface of a water-absorbing recording medium such as paper. An aqueous ink in which a colorant such as a water-soluble dye is added to water is widely utilized as an ink jet ink which is used in such ink jet recording. Meanwhile, in recent years, the ink jet recording has come to be utilized for recording onto surfaces of various types of recording media in various fields. In order to perform the recording onto surfaces of various types of recording media, a non-aqueous ink which does not substantially contain water as a solvent has been therefore developed in place of an aqueous ink.
Specific examples of such a non-aqueous ink include a non-aqueous ink proposed in JP-A-2005-15672, which contains an organic solvent in which polyvinyl chloride can be dissolved, pigment, and resin in order to improve adhesiveness to vinyl chloride-based resin. In addition, another non-aqueous ink composition is proposed in JP-A-2008-274034, which contains a pigment, organic solvent, polyvinyl chloride, and anti-dehydrochlorination reaction agent in order to securely perform adequate printing to vinyl chloride-based resin.
Meanwhile, because an ink which contains a dispersion medium such as resin or pigment is a so-called dispersed system, it is known that such an ink exhibits thixotropic nature. It is believed that the thixotropic nature is caused by the structural change of association due to hydrogen bond of a polar solvent to a dispersed material or is caused by the change of the conformation of resin. Furthermore, it is known that the thixotropic nature has an influence on ink ejection stability during formation of ink droplets in the ink jet recording (particularly in the case of utilizing high frequency, see JP-A-2008-238031).
The typical non aqueous ink is provided assuming that recording is performed to a vinyl chloride-based resin, and a specific solvent such as symmetric glycol diether (glyme) or N-methylpyrrolidone therefore needs to be used. In the case of using such a specific solvent, thixotropic nature adequate to secure ink ejection stability may be unfortunately reduced, and good ejection stability is therefore less likely to be secured.
In an ink set including the typical non-aqueous ink, light resistance may vary depending on the type of pigment to be added. In the case where the ink set partially includes a non-aqueous ink containing a pigment which exhibits small light resistance, the color balance of characters and images which are recorded on a recording medium may be reduced.